1. Field of the Invention
The present invention relates to a catalytic manufacturing method and reaction of an imine having no substituent on a nitrogen, and more particularly, to a method of stably manufacturing imines having no substituent on a nitrogen from an organic azide having α-hydrogen using a suitable metal complex as a catalyst at room temperature under neutral conditions. In addition, the present invention relates to a method of producing various binding products through a reaction between the manufactured imine and an external nucleophile.
2. Discussion of Related Art
The present invention relates to a catalytic method of manufacturing an imine having no substituent on a nitrogen and a reaction of the manufactured imine. It is known that the imine having no substituent on a nitrogen is difficult to be isolated and purified, and particularly, an aldimine having no substituent on a nitrogen is impossibly present in a stable form at room temperature. Meanwhile, some methods of manufacturing an imine having no substituent on a nitrogen have been known. For example, the methods that have been known so far are disclosed in the manufacture through a reaction between oxaziridine and an organic base, DABCO, reported by the Boyd group in 1979 [Boyd, D. R.; Hamilton, R.; Thompson, N. T.; Stubbs, M. E. Tetrahedron Lett., 1979, 20, 3201], allylboration for N-unsubstituted imine generated as an intermediate by reacting water with N-silyl imine reported by the Brown group in 1999 [Chen, G.-M.; Ramachandran, P. V.; Brown, H. C. Angew. Chem. Int. Ed., 1999, 38, 825], allylboration for N-unsubstituted aldimine produced by reacting ammonia to an aldehyde reported by the Kobayashi group in 2004 [Sugiura, M.; Hirano, K.; Kobayashi, S. J. Am. Chem. Soc., 2004, 126, 7182], and allylboration for N-unsubstituted ketimine produced by reacting ammonia to a ketone reported by the Thadani group in 2005 [Dhudshia, B.; Tiburcio, J.; Thadani, A. N. Chem. Commun., 2005, 5551].
However, the above-described examples are all limited to conditions for producing an imine having no substituent on a nitrogen. In synthesis from an oxaziridine, a strong base should be used and fluorenone is generated as a byproduct, and in the Brown method, N-silyl imine should be first synthesized from a reaction between a nitrile and a Grignard reagent. In addition, the method using ammonia should use ammonia at an excessive amount of 20 equivalents or more, and can be applied only to a substrate having no functional group reacting with ammonia, other than aldehyde or ketone. Therefore, a catalytic method of manufacturing an imine having no substituent on various types of nitrogen under mild conditions has not been known until now.
Meanwhile, an organic azide is used as a substrate in various organic reactions capable of forming a new carbon-nitrogen or nitrogen-heteroelement binding. Advantages of the azide compound as a substrate are easiness and diversity of the synthesis, and the azide compound may be synthesized using a halogenated compound, an alcohol, an epoxide, an alkyne, or an amine as a starting material under mild conditions. A reaction using such an organic azide as a reaction material is generally cycloaddition, and some examples of selective decomposition to synthesize a nitrogen-heterocyclic compound have been known. Recently, some examples for equivalent production of a metal-imine complex from an organic azide have been reported [Chiba, S.; Zhang, L.; Lee, J.-Y. J. Am. Chem. Soc. 2010, 132, 7266, Albertina, G.; Antoniuttia, S.; Castro, J. J. Organomet. Chem. 2010, 695, 574], but a catalytic method of manufacturing an imine having no substituent on a nitrogen through selective decomposition of an organic azide has not been known until now.
In addition, since an imine having no substituent on a nitrogen which can stably exist under general conditions has not been known so far, addition of the imine has rarely known, either. Due to such a problem, to obtain an amine adduct that can be obtained through addition, an imine having a substituent on a nitrogen has been used as a starting material. However, such a method has an unavoidable disadvantage of removing a substituent of a nitrogen in the final operation to obtain a necessary amine adduct.
For this reason, a necessity for a method of manufacturing an imine having no substituent on a nitrogen is emphasized.